Change in practice patterns over time for endocrine therapy and radiation therapy in women with breast cancer age 65 and older.

purposeIn 2017, the National Comprehensive Cancer Center (NCCN) recommended omitting radiation therapy (RT) for women aged 70 + with stage 1, hormone receptor-positive breast cancer after lumpectomy. However, the optimal treatment remains uncertain given challenges with delivering endocrine therapy (ET) and RT.

methodsFemales with hormone receptor positive, HER2 negative, clinically node negative breast cancer aged 65 + diagnosed 2012-2021 who underwent lumpectomy with or without axillary surgery at a single institution were included. The treatment groups of ET only, RT only, both ET and RT (ET/RT), and neither ET nor RT were compared by patient age, year of diagnosis, and recurrence rates. Fisher's Exact Test was used to compare treatment groups, and competing risk analysis was used to examine recurrence rates.

resultsOf 383 patients analyzed, 28% received ET only, 8% RT only, 53% ET/RT, and 10% neither ET nor RT. Over time, fewer participants received ET/RT or RT alone and more participants received ET alone or neither ET nor RT (p=.006). Compared to those treated with ET/RT, those treated with neither ET nor RT (hazard ratio [HR] 10.60 [95% CI 4.13-27.21]) and with ET alone (HR 3.02 [95% CI 1.28-7.16]) had higher risk of disease recurrence.

conclusionsFewer participants received ET/RT or RT alone after the NCCN guideline publication. However, these cohorts had lower recurrence risks than those treated with ET only and neither ET nor RT. These results support consideration of larger prospective studies evaluating RT alone following lumpectomy in this population.